<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script src="./vue.global.js"></script>
  <title>Document</title>
</head>
<body>
  <div id="root">
    {{title}}
    <my-header></my-header>
    <my-footer></my-footer>
  </div>
  <script>
    const { createApp } = Vue
    
    const myHeader = {
      template: `
      <header>title</header>
      `
    }

    const app = createApp({
      components: {
        'my-header': myHeader
      },

      data() {
        return {
          title: 'hello'
        }
      }
    })

    app.component('my-footer', {
      template: `
        <footer>copyrights</footer>
      `
    })

    app.mount('#root')
  </script>
</body>
</html>